Chapter 5 (Cell transport)_Russo Grade 11th

Osmosis

Diffusion of water through a selectively permeable membrane

On which side of the membrane are Na+ ions released from the pump?

External

*Phagocytosis*

Phagocytosis is a type of endocytosis in which cells ingest large particles or whole cells.

Pinocytosis involves the transport of...

*B.*...fluids into the cell.

on which side of the membrane are K+ ions released from the pump?

inside

The sodium-potassium pump transports...

*A.*...Na+ out of the cell and K+ into the cell.

The diagrams below represent the six steps in one cycle of the sodium-potassium pump.

*A.* 5 *B.* 4 *C.* 2 *D.* 1 *E.* 6 *F.* 3

Hydrophilic

water loving

exocystosis is a

way for cells to release large molecules such as proteins

cell membranes are selectively permeable. Some solutes can cross the membrane _____, some cross with _____, and others do not cross at all.

-freely -assistance

what happens to the movement of molecules at equilibrium

At equilibrium, movement of molecules does not stop. At equilibrium, there is equal movement of materials in both directions. If a molecule can pass freely through a cell membrane, it will cross the membrane by diffusion

How does the interaction between a carrier protein and the substance it transports resemble the interaction between an enzyme and its substrate?

Both involve the binding of a specific substance to a particular kind of protein and a change in shape of the protein as the process (transport or chemical reaction) proceeds.

How do carrier proteins transport substances across cell membranes?

Carrier proteins bind to a molecule of the substance on one side of the membrane, change shape, transport the molecule across the membrane, and release the molecule on the other side.

Pinocytosis

Cell drinking -transports solute/fluids

Phagocytosis

Cell eating -transports long particles/whole cells

*Concentration Gradient* , *Diffusion*

Concentration gradient is the difference between concentrations. Diffusion is when molecules move to create equalibrium.

Hydrophobic

Water fearing

Describe how a cell produces and releases proteins.

Proteins are made on ribosomes and packaged in vesicles by the Golgi apparatus. The vesicles move to the cell membrane and fuse with it, releasing the proteins from the cell through exocytosis.

describe how a cell produces and releases proteins.

Proteins are made on ribosomes and packaged into vesicles by the Golgi apparatus. The vesicles move to the cell membrane and fuse with it, releasing the proteins from the cell through exocytosis.

What types of stimuli can cause the gate on ion channels to open or close?

Stretching the membrane, electrical signals, or chemicals could cause them to open or close.

contractive vacuole

The cell structure that collects extra water from the cytoplasm and then expels it from the cell

Why is it important that ions being transported across a cell membrane be shielded from the interior of the lipid bilayer?

The interior of the cell the lipid bilayer is nonpolar and repels ions which an attracted to polar environments.

why is it important that ions being transported across a cell membrane be shielded from the interior of the lipid bilayer

The interior of the lipid bilayer is nonpolar and therefore would repel ions, which are attracted to polar environments.

Why is the sodium-potassium transport mechanism called a "pump"?

The mechanism uses energy to move, or pump, Na+ and K+ up their concentration gradient.

What happens to the movement of molecules at equilibrium?

The movement of molecules continues, but there is no net movement in any particular direction.

Explain how a phagocyte destroys bacteria.

The phagocyte forms a pouch in its cell membrane and engulfs bacteria in the pouch. It then pinches off the pouch to form a vesicle. Lysosomes fuse with the vesicle, and lysosomal enzymes destroy the bacteria it contains.

what is the sodium-potassium transport mechanism called a "pump"?

The process of moving sodium and potassium ions across the cell membrance is an active transport process involving the hydrolysis of ATP to provide the necessary energy. It involves an enzyme referred to as Na+/K+-ATPase

What types of stimuli can cause the gates on ion channels to open or close?

The stimuli are stretching of the cell membrane, electrical signals, and chemicals in the cytosol or external environment

How do carrier proteins transport substances across cell membranes?

They bind to the substances, change shape, transport across the membrane, and release the substances on the other side.

sodium-potassium pump

a carrier protein that uses ATP to actively transport sodium ions out of a cell and potassium ions into the cell

ion channels

a complex of protein molecules in a cell membrane that form a pore through which ions can pass

The contractile vacuole of a paramecium should be active when the paramecium is in?

a hypotonic environment

Exocytosis

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

animal and plant cells in a hypotonic solution

animal cells burst but plant cells are fine

facilitated diffusion carrier proteins and cell-membrane pumps both

are specific for the kinds of substances they transport

NA+ ions enter cells by

diffusing through Na+ ion channels

Pinocytosis involves the transport of

fluids into a cell

water always flow to ______

hypertonic

facilitated diffusion is often used to transport?

molecules that are too small to diffuse

on which side of the membrane are NA+ ions released from the pump?

outside

substances that can pass through cell membranes by diffusion include?

oxygen

Many substances need to get into and out of the cell. In order to do so, they must cross the cell membrane. Some of those substances can cross the cell membrane without the need for the cell to use energy. This process is called _____ transport

passive

Endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

The energy needed to power the sodium-potassium pump is provided by the

removal of the phosphate groups from ATP

passive transport

the movement of substances across a cell membrane without the use of energy by the cell

turgor pressure

the pressure that is exerted on the inside of cell walls and that is caused by the movement of water into the cell

When a human red blood cell is placed in a hypotonic environment, it will?

undergo cytolysis

The drawings below show the appearance of a red blood cell and a plant cell in isotonic, hypotonic, and hypertonic environments. Label each environment in the spaces provided.

*A.* Hypotonic *B.* Hypertonic *C.* Isotonic *D.* Hypertonic *E.* Isotonic *F.* Hypotonic

When a human red blood cell is placed in a hypotonic environment, it will...

*A.*...undergo cytolysis.

The contractile vacuole of a paramecium should be active when the paramecium is in...

*B.*...a hypotonic environment.

Facilitated-diffusion carrier proteins and cell-membrane pumps both...

*B.*...are specific for the kinds of substances they transport.

Na+ ions enter cells by...

*B.*...diffusing through Na+ ion channels

Facilitated diffusion is often used to transport...

*C.*...molecules that are not soluble in lipids.

The energy needed to power the sodium-potassium pump is provided by the...

*C.*...splitting of ATP.

Substances that can pass through cell membranes by diffusion include...

*D*...oxygen.

Exocytosis is a...

*D.*...way for cells to release large molecules, such as proteins.

when cells are in isotonic solution, movement of water out of the cell is exactly _____ by movement of water into the cell. A _____ solution of NaCl is isotonic to ______ cells.

-balanced -9% -animal

water moves readily across cell membranes through special protein-loved _____, and if total concentration of all dissolved solutes is not _____ on both sides, there will be net ______ if water molecules into out or out of the cell. Whether there is net movement of water into our out of the cell and which ______ it moves depends on whether the cell's environment is isotonic, hypotonic, hypertonic/

-channels -equal -movement -direction

The simplest type of passive transport is diffusion. _____ is the movement of molecules from an area of _____ concentration to an area of lower concentration. The difference in the concentration of molecules between two ore more areas of a given space is known as the _____ gradient. In passive transport molecules move down their concentration gradient.

-diffusion -high -concentration

Active transport uses ______ to move solute "uphill" against its gradient, whereas in facilitated diffusion, a solute moves _____ its concentration gradient and no _____ input is required

-energy -down -energy

If a plant is not watered, the cells are then in a ______ environment. The water moves out of the cell, the cell membrane moves away from the cell wall, and turgor pressure is lost. This condition is called ______ and explains why a plant wilts.

-hypertonic -plasmolysis

Plant roots are usually found in a ______ environment. This enables water to move into the plants roots through __________. When this happens the vacuole fills, the cell swells, and the cell membrane is pushed against the cell wall. This actions created _____ pressure.

-hyptonic -osmosis -turgor

The surfaces of a cell membrane are _____ the interiors are _____

-hyrdophilic -hyrdohphobic

Another example of facilitated diffusion involves membrane proteins known as ______ channels. Because ions are charged particles, they tend to interact with the interior of the phspholipid bilayer. In order to cross the membrane, they need to move through a channel.

-ion

when water diffuses across the cell membrane it is called _____. This process allows for the movement of water into and out of the cell. The net direction the water moves will depend on the _____ gradient.

-osmosis -concentration

If concentration of dissolved solutes are less _____ the cell than ____, the concentration of water outside is correspondingly greater. When _____ the cell. Cells without cell _____ will swell and may _____ (lyse) if excess water is not removed from the cell. Cells with cell walls often benefit from the _____ pressure that develops in hypotonic environments.

-outside -inside -into -walls -burst -turgor

if concentration of dissolved solutes are greater _____ the cell , the concentration of water outside is correspondingly _____. As a result, water inside the cell will flow ______ to attain equilibrium, causing the cell to ______. As cells lose water, they lose the ability to _____ or _____. Hypertonic environments, such as concentrated brines or ______, have been used for food preservation because microbial cells that would otherwise cause spoilage are _____ in these very hypertonic environments and are unable to function.

-outside -lower -outwards -shrink -function -dividing -syrups -dehydrated

hypertonic comes from the Greek "hyper" meaning ____ and "tonos" meaning stretching. In a hypertonic solution, the total concentration of all dissolved solute particles is _____ than that of another solution, or greater than the concentration in a _____

-over -greater -cell

a few lipohobic (lipid-loving) substances move freely across the cell membrane by _______ _______. Most small molecules or ions require the assistance of ________ _______ to transport them across the membrane. ______ molecules do not cross intact cell membranes, except in certain special cases.

-passive diffusion -protein carriers -large

Membranes consists o _____ _____ combined with a variety of _______ in a fluid _______ arrangement

-phospholipid -bi-layer -proteins -mosiac

most biologically important solutes require ______ carriers to cross cell membranes, by a process of either _______ or ______ transport

-protein -passive -active

when two environments are isotonic, the total concentration of dissolved solutes is the ______ in both of them

-same

Glucose is moved across the membrane by this process because it is too big to move alone. Glucose is transported by a carrier protein. When the molecule binds to the protein, it changes _____. This shields the molecule from the interior of the membrane. The protein then opens up on the other side, and releases the molecule.

-shape

The ability of a molecule to diffuse across a cell membrane is based upon the s_____ and type of molecule, as well as its polarity. Many uncharged, small particles can pass easily across the membrane where many large or polar molecules and ions do not move down their concentration gradient easily. They need help. Another type of passive transport, facilitated diffusion, uses _____ proteins to accomplish this goal.

-size -carrier

What are four ions that are very important for cell functions?

-sodium (NA+) -potassium (K+) -calcium (Ca2+) -chloride (cl-)

different types of stimuli for ion channels

-stretching of the cell membrane -electrical signals -chemicals in the cytosol or external environment.

hypotonic comes form the Greek "hypo" meaning _____ and "tonos" meaning ______. In a hypotonic solution, the total concentration of all dissolved solute particles is ______ than that of another solution or less than that of a _________

-under -stroching -less -another solution

the presence of absence of cell ____ influences how cells respond to osmotic fluctuations in their environment

-walls

Osmosis (movement of ______ across membrances) depends on the relative ____ of solute molecules on either side of the ______

-water -concentration -membrane

Hydrophilic molecules tend to interact with ____ and each other. Hydrophobic molecules ____ interaction with water and tend to interact with other ______ molecules

-water -avoid -hydrophobic

soduim-potassium pump

1. Moves Na+ and K+ ions across the cell membrane 2. Allow nerves to send electrical info. Allows muscles to contract. Allows for the absorption of food &urine

concentration gradient

A difference in the concentration of a substance across a distance.

isotonic solution

A solution in which the concentration of solutes is essentially equal to that of the cell which resides in the solution

hypertonic solution

A solution in which the concentration of solutes is greater than that of the cell that resides in the solution

hypotonic solution

A solution in which the concentration of solutes is less than that of the cell that resides in the solution

isotonic solution

A solution with the same concentration of water and solutes as inside a cell, resulting in the cell retaining its normal shape because there is no net movement of water.

*Vesicle*

A vesicle is a membrane-bound organelle that pinches off from the cell membrane during endocytosis or fuses with the cell membrane during exocytosis.

*Active Transport*

Active transport is the movement of materials across a membrane from an area of lower concentration to an area of higher concentration.

Plasmolysis

Collapse of a walled cell's cytoplasm due to a lack of water

On which side of the membrane are K+ ions released from the pump?

Ctyosolic

*Endocytosis*

Endocytosis is the process by which cells ingest external fluid, macromolecules, and large particles.

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

hypotonic

Having a lower concentration of solute than another solution

*Hypertonic* , *Plasmolysis*

Hypertonic is when a solution has a higher concentration of solute molecules outside the cell. Plasmolysis is when they shrink due to this.

Explain how a phagocyte destroys bacteria.

If forms a pouch in its cell membrane and engulfs bacteria in the pouch. It forms a vesicle. It then fuses with lysosomes and the enzymes digest the bacteria.

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

the sodium-potassium pump transports

Na+ out of the cell and K+ into the cell

*Osmosis* , *Turgor Pressure*

Osmosis is the process in which water molecules diffuse across the cell membrane. Turgor pressure is the pressure of water pushing against the cell wall in a plant.

How does the interaction between a carrier protein and the substance it transports resemble the interaction between an enzyme and its substrate?

They both involve binding to a substance and changing shape while leaving the enzyme or protein unchanged.

Cytolysis

This happens when a cell swells until pressure bursts it, resulting in cell death.

hypertonic

when comparing two solutions, the solution with the greater concentration of solutes

isotonic

when the concentration of two solutions is the same